<body>
	<div>
		{% block header %}
			<p> this is header </p>
		{% endblock %}
	</div>
	<div>
		{% block content %}
			<p>this is content</p>
		{% endblock %}
	</div>
	<div>
		{% block footer %}
			&copy; Copyright 2018 by <a href="http://www.shiyanlou.com/">shiyanlou</a>
		{% endblock %}
	</div>
</body>